U.S. patent number 5,296,803 [Application Number 07/957,758] was granted by the patent office on 1994-03-22 for watt-hour meter cover with battery hatch/reset switch and optical communication port.
This patent grant is currently assigned to Landis & Gyr Metering, Inc.. Invention is credited to Christopher J. Gatz, Lane C. Kirby, Lester C. Moore, Ronald C. Tate.
United States Patent |
5,296,803 |
Kirby , et al. |
March 22, 1994 |
Watt-hour meter cover with battery hatch/reset switch and optical
communication port
Abstract
A watt-hour meter cover is provided which has an optical coupler
including a conduit, lens, and means for engaging an external
programmer/reader. The conduit is has improved signal transmission
properties. The cover may be designed to disable test mode hardware
when replaced after meter servicing. A battery access hatch and
module with a reset and scroll actuator is installed through the
cover.
Inventors: |
Kirby; Lane C. (West Point,
IN), Moore; Lester C. (West Lafayette, IN), Gatz;
Christopher J. (West Lafayette, IN), Tate; Ronald C.
(Battle Ground, IN) |
Assignee: |
Landis & Gyr Metering, Inc.
(Lafayette, IN)
|
Family
ID: |
23627062 |
Appl.
No.: |
07/957,758 |
Filed: |
October 7, 1992 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
|
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719246 |
Jun 21, 1991 |
|
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410980 |
Sep 22, 1989 |
5049810 |
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Current U.S.
Class: |
324/156; 324/157;
324/96 |
Current CPC
Class: |
G01R
22/065 (20130101) |
Current International
Class: |
G01R
11/00 (20060101); G01R 11/04 (20060101); G01R
001/04 (); G01R 019/16 () |
Field of
Search: |
;324/156,157,96,116,142,13R,110 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Karlsen; Ernest F.
Attorney, Agent or Firm: Woodard, Emhardt, Naughton,
Moriarty & McNett
Parent Case Text
This application is a continuation of application Ser. No.
07/719246, filed Jun. 21, 1991, now abandoned, which is a division
of application Ser. No. 07/410,980, filed Sep. 22, 1989, now U.S.
Pat. No. 5,049,810.
Claims
What is claimed is:
1. A cover for mounting on an energy consumption meter having a
radiation signal transmitter for external communication with an
external reader, the cover comprising:
a cover body having means for engaging an energy consumption
meter;
communication pathway means for conducting a radiation signal from
a transmitter in the meter, said pathway means including;
an elongated conduit body having a pair of opposite ends;
means for supporting said conduit body on said cover body for
communicative alignment of one end of said elongated conduit body
with the transmitter when said cover body is mounted on the meter,
said means mounting the other end of said conduit body to said
cover body with said elongated conduit body extending toward the
transmitter; and
means integral with said conduit body for enhancing transmission of
the radiation signal through the interior of said conduit body by
enhancing internal reflection of the signal therewithin; and
engagement means for engaging an external reader in communication
with said other end of said elongated conduit body.
2. The cover of claim 1 wherein said engagement means is
paramagnetic.
3. The cover of claim 2 wherein said engagement means includes;
a powdered metal ring; and
means for supporting said ring adjacent said other end of said
conduit body.
4. The cover of claim 1 wherein said conduit body is formed
separate from said cover body and said means for supporting said
conduit body includes an opening defined in said cover body adapted
to receive said conduit body therethrough with said other end of
said conduit body mounted outside said cover body.
5. The cover of claim 4, wherein said means for supporting said
conduit body includes:
a flange defined in said conduit body adjacent said other end, said
flange being sized larger than said opening defined in said cover
body; and
retaining means for engaging said conduit body to thereby retain
said cover body between said retaining means and said flange when
said conduit body extends through said opening defined in said
cover body.
6. The cover of claim 5 wherein said conduit body includes a
cylindrical portion extending from said flange, said cylindrical
portion having a first diameter along a first section adjacent said
flange, and a reduced second diameter along a second section
adjacent said one end of said conduit body.
7. The cover of claim 5 wherein said retaining means is a lock
washer.
8. The cover of claim 1 wherein;
said elongated conduit body is cylindrical and substantially solid
throughout; and
said means for enhancing transmission includes a polished external
surface of said conduit body.
9. The cover of claim 8 wherein said conduit includes means for
fastening said engaging means to said meter cover.
10. The cover of claim 1 wherein said means for enhancing
transmission within said conduit body includes two parallel
substantially semi-circular bores defined therethrough from said
one end to said other end.
11. The cover of claim 1 wherein said means for enhancing
transmission includes a coating on at least a portion of the
external surface of said conduit body, said coating being opaque to
the communicated signal.
Description
BACKGROUND OF THE INVENTION
This invention relates generally to watt-hour meter covers and more
particularly to watt-hour meter covers featuring enhanced access to
and reliability in the operator interactive controls and displays
of the meter.
The importance of interactive communication in energy consumption
metering is recognized. For example, U.S. Pat. No. 4,638,314 to
Keller discloses a remotely-read energy meter to which an
electronics package has been added, the package includes a thin
annular printed circuit board mounted for support on an annular
adapter ring and disposed in surrounding relation to the annular
watt-hour meter. Electrical components mounted on the printed
circuit board provide an electronic read-out circuit for a pulse
initiator, and further provide the transponder electronics for
effecting bidirectional communication between the watt-hour meter
and a remote location.
U.S. Pat. No. 4,783,623 to Edwards et al. discloses a device for
converting standard electric meters to programmable interactive
meters. The device includes a circuit for measuring energy use and
is designed for installation below the rotating disc of a standard
meter.
In response to the need for interactive communication, modern
electric energy meters are equipped with operator interactive
controls and readouts. A reset switch which is mechanically
activated through hardware mounted to and passing through the face
of the meter cover is typically present to enable resetting of the
meter after energy consumption has been recorded. An LED indicator
for calibration purposes pulses in relation to the power being
measured. An infrared (IR) emitter/detector operates to
bidirectionally exchange data and control commands with utility
personnel and/or electronic data handling devices through an
optical communication port mounted on the face of the meter.
Communication between the fixed IR emitter/detector and the
portable reader/programmer occurs through the transparent cover of
the meter.
Problems are encountered in the design of the present systems. One
problem arises since reset switch hardware normally has metal
parts. Consequently, it is an entry point for electrostatic
discharge (ESD) which can damage circuit components of the printed
circuit board of the register. The IR emitter/detector has adequate
power and sensitivity to operate only within very restricted
ranges, alignment, and ambient light conditions. One solution to
this problem has been to increase the distance between the register
face and the meter cover face to reduce the incidence of ESD damage
through the metallic hardware. This has made optical communication
less reliable due to increased distance and greater exposure to
interfering ambient light, mandating the use of specially designed
meter covers to provide the necessary accuracy of cover to register
spacing and precise alignment of the optical communication port
with the emitter/detector to assure reliable operation over the
full range of assembly tolerances and other manufacturing and
service variables.
Improvement of signal transmissions in photo coupling devices has
been a subject of some interest. U.S. Pat. No. 4,712,017 to
Kamasaki shows a photo coupler device which comprises a light
emitting element and a light receiving element made of a four layer
structure of PNPN conductivity wherein a portion of the light
receiving element through which the light enters does not
contribute to its operation is covered with a light reflecting
membrane. Various configurations facilitating interactive
communication in energy consumption meters have been proposed. U.S.
Pat. No. 4,298,839 to Johnston is an example of an electric energy
meter having a programmable time base measuring system. A radiation
sensitive external data interface receives and transmits data
through a transparent communications window of the meter cover. The
cover is provided with accurately spaced conical recesses which
mate with projections on the programmer/reader. A radiation
shielding baffle is mounted in the meter housing enclosed by the
cover.
U.S. Pat. No. 4,584,527 to Amigo discloses a watt-hour metering
system including a meter enclosed in a transparent cover and having
an electronic register with a multichannel infrared responsive I/O
port in a portable electronic programmer/reader having a
complimentary infrared data I/O port. Inside the cover, the meter
includes a pivoting shutter having a pair of magnets affixed
thereto and held by gravity in a position to shield at least one
channel of the I/O from radiation entering the cover. An activating
magnet is affixed to the programmer/reader such that when the
programmer/reader is placed against the meter cover, magnetic flux
is coupled to the shutter magnets to cause the shutter to pivot and
permit the transmission of infrared radiation. Alternatively, a
shutter is pivotally secured to the cover and manually operable
from outside the cover to selectively permit and prevent
transmission of radiation.
U.S. Pat. No. 4,491,793 to Germer et al discloses a meter cover
mounted receptacle and attachable magnetic coupler incorporating
optical communication devices for communicating with electric
circuitry housed within the meter cover. An umbilical cable enables
an infrared emitter and detector to be assembled to the inside face
of the meter cover directly inside the optical port hardware, thus
controlling distance, alignment and ambient light.
Significant advantages in tooling cost and product lead time may be
realized if it is possible to update meters using their existing
glass or plastic covers. Certain designs presently in manufacture
seek to improve upon the lack of manufacturing latitude imposed by
the factors discussed above. One design, available from Landis
& Gyr Metering, Inc. as PDR-A.TM., uses an electrically
insulated reset switch to prevent entry of electrostatic discharge
and thereby significantly reduces the cover-to-register space and
thus the optical communication distance. This design, however,
still requires a specially designed plastic cover to maintain the
minimum spacing requirement and to provide the fine detail
necessary to integrate the optical port into the end of the cover.
Moreover, the insulating materials used in the reset switch do not
have sufficient rigidity to facilitate an adjustment feature
required to accommodate existing covers.
The design shown in Germer et al using an umbilical cable allows
the cover depth to be varied by the designer as required to
accommodate reset hardware or utilize existing cover designs
without concern for optical communication reliability. The
umbilical cable from the register to the optical port in the meter
cover, however provides a solution that is awkward to handle and
assemble, making access to the meter face difficult, and is
relatively expensive to manufacture due to the number of additional
components.
Consequently, there remains a need for an optical port design which
efficiently transmits optical signals and yet offers simple
assembly, ease of service, ruggedness and accommodates other meter
design considerations. Most advantageously, such an optical port
would be readily retrofitted to existing covers to preserve the
investment in such.
Meters are commonly equipped with test mode switches which enable
the meter operator to determine whether the meter is functioning
properly or is in need of service. Commonly, these switches are
accessed by removing the cover of the meter. It often occurs that,
after testing the meter, the operator neglects to disengage the
test mode switch. Because the meter is left in the test mode it
does not record energy consumption. There is a need for test
hardware design that addresses this problem.
With respect to other features of modern meters, it has been
recognized that access to the meter battery and scroll and reset
switches without the necessity of removing the meter cover is
advantageous. Further, external access to the battery and switch
actuators should be limited to prevent tampering. In this regard,
various designs for switch actuators have been proposed. For
example, U.S. Pat. No. 3,908,166 to Shackford discloses a watt-hour
meter cover mounted rotary reset actuator incorporating a
combination key operated, tamper resistant security lock and a
rotary motion limiting device preventing application of excessive
torque.
U.S. Pat. No. 4,074,192 to Hart discloses an external manual
mechanism for resetting a cumulative demand register. The mechanism
can be simply locked and unlocked for periodic use and may be
applied to cumulative demand registers on watt-hour meters. A
plunger with an arm pushes the reset crank. The mechanism is
spring-biased in the disengaged mode.
U.S. Pat. No. 4,188,575 to Palmer et al discloses a meter cover
mechanism incorporating a combination key operated tamper resistant
security lock and externally controllable meter reset actuator and
a meter access hatch. The reset switch is contacted by an actuator
arm if the key is turned in the proper direction with the hatch
closed. Access to the programmer probe is provided when the hatch
is opened. Insertion of a battery replacement tool into the open
hatch is suggested.
U.S. Pat. No. 4,602,211 to Losapio et al discloses an electronic
demand register for an electric meter including a plurality of push
button controls for controlling material displayed or a mode of
operation of the demand register. A lockable switch actuator
includes an actuating paddle within a cover or housing of the meter
which, when unlocked, can be rotated into alignment with a selected
one of the push button controls and then pushed inward to actuate
the selected push button control.
Efforts have also been directed to providing restricted access
hatches. U.S. Pat. No. 4,688,146 to Newmark et al is exemplary. A
three piece molded plastic enclosure for service entry into
apparatuses such as meters, fuses, circuit breakers, and switches
is disclosed. The enclosure provides protection against adverse
environmental conditions, while providing visual access to the
components contained therein. The enclosure is tamper proof by
virtue of a hinge arrangement formed between a stationary cover and
a movable door. Once the door is assembled to the cover, the door
cannot be easily removed without a separate tool.
Easy servicing of meter batteries is recognized as desirable. U.S.
Pat. No. 4,791,362 to Philpot discloses a module meter assembly
including a replaceable battery modules. An adaptor used with the
meter assembly provides for retrofitting an improved modular
structure on existing meters to permit upgrading of the functions
performed by the existing meters. The modular device is designed
for installation beneath the cover of the meter.
Further, some meters provide access to the meter battery without
removing the meter cover. U.S. Pat. No. 4,075,561 to Stevens
discloses an electrical apparatus enclosed within a housing
containing a replaceable battery. Means for programming and for
testing by means of connectable electrical contacts with an
independent instrument are provided. The electrical apparatus is
provided with a composite unit comprising a battery support and an
electrical terminal connector which is arranged to cooperate with a
single access port in the apparatus housing whereby routine
servicing of battery replacements, programming and/or testing can
be performed through a single port.
U.S. Pat. No. 4,297,635 to Stevens discloses an apparatus for
retaining a replaceable battery comprised of a unitary structure
having a chamber therein for receiving a battery and a resilient
retaining means cooperating in the chamber with the battery
provides a structure for easily replacing the battery. The
apparatus is particularly adaptable to a programmable electrical
watt-hour meter where a battery and programming connector in the
watt-hour meter may be accessed through an access port in a housing
of the watt-hour meter to replace the battery and service the
watt-hour meter.
U.S. Pat. No. 4,713,679 to Losapio et al discloses a case including
a hatch which permits removal and replacement of a battery without
removing the case from the meter. In one embodiment the battery is
installed in a battery clip on the face plate on the meter which is
accessible through the hatch. An extra length of wires from the
battery permits the battery and its miniconnectors to be withdrawn
through the hatch for replacement thereof. In a second embodiment
of the invention, the battery is captured in a durable hatch and is
withdrawn from the meter by the action of opening hatch. In this
embodiment, the hatch may be hinged or not hinged.
As demonstrated by the foregoing, the need for efficient access to
the scrolling, resetting functions and routine maintenance aspects
of watt-hour meters is understood. Until the present, this need has
not been adequately addressed in a combined battery access hatch
and locking reset and test switch assembly structure.
SUMMARY OF THE INVENTION
Accordingly, the present invention addresses these needs in a cover
for an energy consumption meter having a radiation signal
transmitter for external communications with an external reader.
The cover is mounted on the meter and has a communication coupler
assembly creating a signal communication pathway between the
transmitter and the external reader. The cover includes a cover
member, a conduit for conducting the transmitted radiation signal.
The conduit is mounted in the cover for communicative alignment of
a solid portion thereof along its length with the transmitter when
the cover is mounted on the meter and includes enhanced internal
reflection of the transmitted signal. Further included is a portion
for engaging the reader with the coupler.
A further aspect of the present invention involves a cover for an
energy consumption meter having a radiation signal transmitter for
external communications with an external reader with the cover
mounted on the meter and having a communication coupler assembly
creating a signal communication pathway between the transmitter and
the external reader including a conduit for conducting the
transmitted radiation signal. The conduit is mounted on the cover
for communicative alignment with the transmitter when the cover is
mounted on the meter and is formed substantially from a solid
material which is opaque to the transmitted signal and has at least
one signal transparent channel therethrough. A window is provided
at one end of the conduit along with provision for engaging the
external reader with the coupler assembly about the conduit.
A further aspect of the present invention is in combination, an
energy consumption meter having a test mode and a removable and
replaceable cover, including a meter body having a side and a test
switch pivotally mounted in the side. The switch is operable when
pivoted outward from the side to initiate a test mode of the meter
and inoperable when pivoted at least flush with the side. The cover
includes a cover member having a continuous side wall. The side
wall has a rim defining an internal diameter sufficiently small
that upon replacement of the cover over the meter body, the rim
engages the switch if the switch is in its test mode position to
pivot the switch to its inoperable position thereby disabling the
test mode.
In a still further aspect of the present invention, a cover for an
energy consumption meter having a meter body with a battery mounted
therein and a cover mountable over the body and having a modular
battery access hatch assembly includes a cover member, a hatch
opening defined in the cover member for access to the battery
therethrough, a hatch cover mountable over the opening to close
said hatch opening and a resetting switch carried by said hatch
cover for actuating the reset mode hardware externally of the meter
cover. The reset switch is normally biasing away from said reset
hardware. Also included is a latch for latching the hatch cover
onto the meter cover.
It is an object of the present invention to provide an improved
watt-hour meter cover.
It is another object of the present invention to provide a
watt-hour meter cover with an improved optic coupler assembly
therethrough.
It is a further object of the present invention to provide a
watt-hour meter cover which, upon replacement, disables test
hardware.
It is a still further object of the present invention to provide a
watt-hour meter cover with improved battery access and reset/scroll
hardware.
Other objects and advantages may be readily discerned to those with
skill in the art to which the invention pertains after reviewing
the following written description and accompanying figures.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front perspective view of an optical coupler of the
present invention installed through a standard meter cover.
FIG. 2 is a partial cross-sectional view through the cover and face
of a watt-hour meter showing a first alternate optical coupler
assembly made according to a first embodiment of the present
invention.
FIG. 3 is a perspective view of a second alternate of the first
embodiment according to the present invention.
FIG. 4 is an elevational view of a conduit made according to a
third alternate of the first embodiment of the present
invention.
FIG. 5 is a cross-sectional view of the conduit of FIG. 4 taken
along line 5--5 and looking in the direction of the arrows.
FIG. 6 is a partial cross-sectional view of a conduit assembly
including the conduit of FIG. 4.
FIG. 7 is an exploded perspective view of a meter cover including
the assembly of FIG. 6.
FIG. 8 is a partial elevational view of a test and reset switch
made according to another aspect of the present invention.
FIG. 9 is a partial elevational view of a reset switch according to
the present invention showing the cover being replaced.
FIG. 10 is a perspective elevational view of a module assembly made
according to a further embodiment of the present invention.
FIG. 11 is an exploded perspective view of the module assembly of
FIG. 10.
FIG. 12 is a front perspective view of a meter cover made according
to the present invention with a hatch for access to the battery
module of FIG. 10.
FIG. 13 is a front elevational view of a latch assembly made
according to the present invention with the component parts in the
scroll mode.
FIG. 14 is an exploded view of the hatch cover assembly of FIG.
13.
FIG. 15 is a front elevational view of the latch assembly of FIG.
13 with the component parts latched.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For the purposes of promoting an understanding of the principles of
the invention, reference will now be made to the embodiments
illustrated in the drawings and specific language will be used to
describe the same. It will nevertheless be understood that no
limitation of the scope of the invention is thereby intended, such
alterations and further modifications in the illustrated devices
and methods, and such further applications of the principles of the
invention as illustrated therein being contemplated as would
normally occur to one skilled in the art to which the invention
relates.
FIG. 1 illustrates a watt-hour meter 19 and optical coupler
assembly 20 according to a first embodiment of the present
invention installed through cover 26 thereof. Optical coupler
assembly 20 creates a signal communication pathway between infrared
emitter/detector 21 (FIG. 2) and an external reader (not shown).
The meter shown is a standard resettable watt-hour meter. For
example, the meter may be one similar to PDR-A available through
Landis & Gyr Metering, Inc. of Lafayette, Ind. External reset
hardware 29 is present through cover 26 for resetting the
cumulative energy consumption counter after the meter has been
read. For engaging an external reader/programmer, port ring 30 is
configured to mate with the probe of the reader/programmer. In FIG.
1 port ring 30 is shown to have an outer annulus 33 enclosing
horseshoe-shaped projecting shoulder 32. This design corresponds to
a similar but matingly opposite female portion of the
reader/programmer probe. Typically, the probe has a magnetically
inductive portion so that port ring 30 is preferably made of
paramagnetic material, preferably steel. The preferred embodiment
is powdered metal. The horseshoe shape of shoulder 32 and the
corresponding portion of the probe, requires that the probe and
coupler assembly 20 can only be mated in one relative position. In
the relative position, the flat part of the horseshoe receives the
flat part of the probe. This relative position is preferably the
position of maximum signal alignment. Consequently, the necessary
alignment of the probe and coupler is easily achieved upon
engagement of the probe and the coupler. It will be understood that
other configurations also would provide mating alignment of the
probe and the coupler and no limitation is inferred by the
foregoing description.
FIG. 2 is a partial cross-sectional view through the face and cover
26 of a watt-hour meter showing a first alternate optical coupler
assembly made according to the first embodiment of the present
invention. The arrangement of the individual parts of coupler
assembly 20 provides an environmental seal as well as an engagement
for the external reader and a transparent window allowing the
emitted signal to pass from the emitter on the meter face through
the meter cover and into the external reader. Emitter/detector 21
is present on printed circuit board 22. Tunnel 23 is mounted in
register face plate 24 in optical alignment with emitter/detector
21. A portion 25 of tunnel 23 is transparent to the infrared signal
emitted by emitter/detector 21. As shown in FIG. 2, transparent
portion 25 is a bore through tunnel 23. Mounted on meter cover 26
is optical coupler 20 aligned with bore 25 to create a signal
communication pathway between emitter/detector 21 and the external
reader. Optical coupler 20 includes solid conduit 27, window 28,
port ring 30 and lock washer 31. Port ring 30 is designed as
described above in connection with FIG. 1. Conduit 27 and window 28
are inserted therethrough. The internal diameter of port ring 30
widens creating surface 34. Against this surface abuts lip 35 of
window 28. As a consequence of the abutting arrangement of lip 35
and surface 34, window 27 retains port ring 30 against meter cover
26. Lock washer 31 secures conduit 27 within cover 26 by exerting a
securing force against the circumference of conduit 27 and inside
surface 38 of cover 26. To enhance the fastening and environmental
sealing functions of coupler 20, a sealant may be applied between
the mating surfaces of the various components of the coupler, for
example at mating surface 37. Any sealant commonly used for this
purpose may be used. The choice of sealant will be readily apparent
to those familiar with the art to which this invention
pertains.
A signal from emitter/detector 21 passes through tunnel 23,
entering conduit 27 where it passes through window 28 and into the
probe of the external reader/programmer matingly engaged with
coupler 20. A signal from the reader/programmer probe to
emitter/detector 21 travels the same path but in the reverse
direction. Conduit 27 is solid to transmit the emitted signal with
high optical efficiency due to increased total internal reflection.
In the preferred embodiment the external surface is polished to
enhance internal reflection. Such a solid is commonly referred to a
"light pipe". The light pipe configuration retains window 28 flush
with the coupling surface 39 of the coupler while conduit 27
extends toward emitter/detector 21 as far as required, allowing for
assembly tolerances. The innermost surface 36 of conduit 27 is,
therefore, quite close to the emitting and detecting elements of
the meter. More signal energy is thus intercepted. The energy so
intercepted is effectively carried within the conduit while ambient
light is nearly effectively excluded. The described configuration
of conduit 27 minimizes the total signal distance which is extended
through air. In general, passage through air reduces the
reliability of the signal. To enhance the exclusion of ambient
light, the outer surface 39 of conduit 27 can be provided with an
opaque coating such as a black coating. Further, to enhance
internal reflection a coating having an index of refraction greater
than the light pipe can be used. Of course, signal receiving
portions such as surface 36 and window 28 should not be so coated.
In addition, tunnel 23 is preferably made of an opaque material and
most preferably black. The preferable material for constructing
conduit 27 and window 28 is plastic and most preferably acrylic,
although other materials having the requisite signal transparency
and transmission characteristics may be used. The conduit and
window are preferably molded and of unitary construction, although
other commonly used methods of manufacture are suitable.
FIG. 3 is a perspective view showing of a second alternative of the
first embodiment according to the present invention. Conduit and
window assembly 40 is shown with window 41, cover abutting surface
42 and lock surface 43 for receiving a lock washer. Stepped down
portion 44 is smaller in outer diameter than lock surface 43. Two
hollows 45a and 45b are formed parallel to the longitudinal axis of
assembly 40. Solid signal transmission pathway 47 is disposed
between the hollows. Assembly 40 is installed in a meter cover in
the manner described above. The outside surface of a meter cover
abuts surface 42. A lock washer such as that shown in FIG. 2 grasps
surface 43. The length of surface 43 is sufficient to accommodate
covers of different thicknesses while still supplying a grasping
surface for the lock washer. The external surface of assembly 40,
exclusive of surfaces in the signal pathway, are optionally
provided with opaque coating 46 to minimize signal interference
caused by ambient light. Most preferably, coating 46 is black.
Stepped down portion 44 prevents coating 46 from being scraped by
placement of the lock washer.
Hollows 45a and 45b are provided to reduce the quantity of plastic
required to make each assembly 40 while improving the optic
characteristics as well. As described above, the conduit and window
are preferably made of molded plastic. In molding, molten plastic
is molded to the desired shape and allowed to cool. Cooling of the
plastic typically is not uniform throughout, plastic near the
surface cooling faster than plastic in the center. Generally,
uneven cooling rates of molten material used to form assembly 40
cause imperfections in the density, etc of the assembly. These
imperfections distort the transmitted signal. Increasing uniformity
of cooling results in improved optical properties. Hollows 45a and
46b increase the surface area of the assembly so cooling takes
place more evenly. Consequently, improved cooling rates, cost
efficiency and desirable optical characteristics from light pipe
type signal transmission are provided by this alternate of the
present invention.
The coupler assemblies described above may be easily retrofitted to
existing meter covers. To retrofit a coupler assembly to an
existing cover, a hole of appropriate diameter is drilled through
the glass or plastic meter cover. The window/conduit/port ring
assembly is inserted through the resulting hole. A lock washer is
placed around the portion of the conduit on the inside of the
cover. If a sealant is used, the sealant is preferably spread on
the appropriate surfaces before insertion.
The length of the light pipe is readily adaptable to the
requirements of a particular meter and its cover. Since the length
of the signal path varies depending on the meter face stackup, the
relative length of the conduit can be varied accordingly to achieve
the optimum result. In meters having covers relatively far above
the meter itself, for example, to reduce ESD damage, the light pipe
may be longer to account for the additional space. In meters having
covers more closely spaced to the register plate, the light pipe
may be shortened.
The primarily solid light pipe of the present invention has
produced about a ten fold increase in the millivolt output of the
detector, making communication with the detector/emitter far more
reliable. Using this type of coupler allows the meter designer to
use virtually any existing or proposed meter cover design and/or
reset hardware design otherwise suitable for the application. Only
minor design consideration needs to be given to the optical coupler
itself. The present invention also provides ease and economy of
manufacture and assembly due to the minimum number of parts
required and the simple way the coupler is installed on the meter
cover. Ease in field service handling is provided by the lack of an
umbilical cable connection, ease of field cleaning operations and
the ruggedness of the assembly. Flexibility results from the
inherent adaptability of the coupler to varying cover height.
Economy and reduced manufacturing lead time results from the
ability to use existing cover designs in many cases, while allowing
relaxation of manufacturing constraints on alignment and spacing
variation. The total distance that a signal must travel through air
is minimized, increasing reliability. Ambient light interference is
minimized by the inherent total internal reflectance and by the
optional opaque coatings. Moreover, the design creates a system
which is more tolerant to misalignment of the emitter/detector and
the reader/programmer.
A third alternative optical coupler assembly according to the first
embodiment of the present invention is depicted in FIGS. 4 through
7. FIG. 4 is an elevational view of conduit 50. Conduit 50 is
primarily in the shape of a closed horseshoe having a flat bottom
surface 51. Conduit 50 has forward projection 52 which is
substantially 8-shaped. Each loop of the eight forms a channel, 53a
and 53b respectively, for through which the signal passes.
FIG. 5 is a cross-sectional view of conduit 50 taken through line
5--5 of FIG. 4 and looking in the direction of the arrows. Conduit
50 has rearwardly projecting lip 54 and may be provided with ridge
55 to facilitate ultrasonic welding according to processes which
are familiar with the art to which the invention pertains.
FIG. 6 is a partial cross-sectional view of coupler assembly 20'
made according to the third alternate of the present invention.
Cover 56 has been specially formed to accommodate conduit 50 and
the other elements of coupler 20'. Conduit 50 is shown
ultrasonically welded to cover 56 at mating surface 57. Ultrasonic
welding causes ridge 55 to melt, adhering to surface 57 and thus,
joining conduit 50 with cover 56. Projections 52a and 52b extend
forwardly into window 58. Window 58 is formed integrally with cover
56 as an externally projecting solid horseshoe. Annular groove 59
is formed on the outer surface of the cover about window 58 to
accommodate and fixedly receive flange 60 of port ring 61.
Preferably, flange 60 is ultrasonically welded to cover 56. Port
ring 61 is formed with a window 62 therethrough for accommodating
signal transmission between the infrared emitter/detector and the
external reader/programmer. In addition, UV filter 63 may be
provided between window 58 and port ring 61. In the case where a UV
filter is provided, such filter has a portion 64 formed in a shape
corresponding to window 62 and inserted therethrough.
FIG. 7 is an exploded view of a meter cover assembly including an
optical port according to the present invention, further
illustrating the relationship of the component parts of optical
coupler 20'.
As described in connection with the first and second alternates of
the present invention, an external reader/programmer is matingly
engaged by port ring 61. For this purpose, port ring 61 is
preferably made of paramagnetic material, and most preferably
powdered metal. Upon mating alignment of the external
reader/programmer with optical coupler 20' creating a communication
pathway with emitter/detector, signals are received by and sent
therefrom. Conduit 50 is preferably made of plastic and preferably
black plastic. Most preferably, conduit 50 is made of black
polycarbonate. Cover 56 is also preferably made of plastic and most
preferably clear polycarbonate. Filter 63 is preferably made of
blue polycarbonate. In addition, port ring 61 may be
chrome-plated.
It will be understood that the invention is not limited to infrared
signal emitters. Other signal types may also be communicated
through the coupler of the present invention. Further, the
emitter/detector may act as only a detector or only an emitter. In
other words, the present invention improves transmission between a
meter and an external reader regardless of the direction of the
signal path, or, in general, the type of signal transmitted.
A second embodiment of the present invention concerns a cover
actuated test mode switch. This embodiment is illustrated in FIGS.
8 and 9. FIG. 8 is a partial elevational view of such a test switch
70. The meter housing is shown with its cover removed. Switch 70 is
shown on a side 71 of a meter module assembly. In the view of FIG.
8 the test switch is in the disabled mode. The switch has a
scroll-like shape with outwardly projecting tab 72 for manual
engagement to forwardly move the switch into the test enabled mode.
A pair of pins 73a and 73b (shown in phantom) are lodged within the
meter housing to provide pivotal action thereabout. A deformable
dome contact 74 (shown in phantom) lies beneath switch 70. Contact
74 is pressed by edge 79, enabling the test mode, when switch 70 is
pivoted forward about pins 73a and 73b.
FIG. 9 shows switch 70 in the test mode. Cover 75 is shown being
replaced after removal for meter function testing. Leading edge 76
of cover 75 engages tab 72 of switch 70 forcing switch 70 to pivot
clockwise about pins 73a and 73b and into the testing disabled
mode. Leading edge 76 will generally be the locking ring which
locks the meter cover together with the meter housing. The
resetting action of meter cover 75 is facilitated by the diameter
of its sidewall 77. This sidewall is formed of a diameter
sufficiently small to engage tab 72 of switch 70. Of course the
diameter of the cover sidewall 77 must be sufficiently large that
switch 70 is not engaged while the cover is being removed. To
further prevent engagement during cover removal, switch 70 may be
made to snap into place once it passes a certain point in its
clockwise movement.
When an operator services a meter, he places it in test mode to
test the metering functions. Often, the operator will neglect to
disable the test switch and the meter remains in the test mode
until the next service period. While in test mode, a meter
typically does not record cumulative energy consumption. Thus, if
left in the test mode the meter will not perform the function for
which it was designed. The configuration of cover 75 and test
switch 70 prevents switch 70 from accidentally being left in the
test mode after meter servicing has been performed. Replacement of
cover 75 will always result in disabling of test switch 70,
alleviating a common problem with meter servicing.
A third embodiment of the present invention is illustrated in FIGS.
10 through 14. It is often desirable to replace the reset and
scroll switch actuator 29 shown in FIG. 1 with a actuator to which
access is limited. The present invention is accordingly an ideal
manner of achieving this end, among others. FIG. 10 is a
perspective elevational view of the external side of a module
assembly made according to the present invention and adapted to be
installed on a meter such as that shown in FIG. 1. Cover disabled
test switch 81 is shown in combination with module 80. The
combination thereof is optional. The structure and operation of
test switch 81 is as described in connection with FIGS. 8 and 9
above and will not be discussed further here. Module 80 is further
provided with battery compartment 82 and scroll/reset access port
83. A battery may be mounted in compartment 82 by a conventional
battery clip, although other mounting methods are contemplated. One
purpose of module 80 is to provide convenient access to the meter
battery which must be available for testing and service on a
periodic basis.
FIG. 11 is an exploded perspective view of the inside of module 80.
Module housing 80 is provided with opening 83 for receiving the
male end 99 of wedge-shaped plunger 84. Opposite male end 99,
wedge-shaped plunger 84 is keyed for the D-shaped cross-section of
post 85 on actuator 86. Actuator post 86 is further provided with
paddle 87 for contacting dome switches 88 and 89 (seen in phantom).
A torsional spring 91 is present between post 85 and plunger 84 for
biasing paddle 87 away from either dome switch. Module housing 90
is adapted to mate with board 92. Board 92 is affixed to housing 90
by means of screw 93 which is threadingly received into column 94.
For connecting switches 88 and 89 with a printed circuit board of
the meter (not shown), connector 95 is provided. Ribbon cable 96
connects connector 95 with the dome switches.
FIG. 12 illustrates a meter cover 98 which has been modified to
facilitate access to module 80. This modification includes hatch
100 having opening 101 for access to module 80 which has been
incorporated into the meter. Hatch 100 includes an adhesive-backed
gasket 102 for sealing hatch cover (FIG. 13) against hatch 100.
Gasket 102 provides a seal preventing environmental elements from
interfering with the integrity of the meter components.
FIG. 13 is a front elevational view of hatch cover 103 with the
locking parts unlocked and in the scroll mode. Knob 104 is shown
rotated clockwise approximately one eighth turn. Latch 105 has been
rotated counterclockwise one quarter turn to unlock the battery
hatch for removal of hatch cover 103, if so desired. After the knob
and latch are rotated, hatch cover 103 can be easily removed by
pulling latch 105 in a direction away from the meter. Hatch cover
103 may then be taken off to expose battery compartment 82 and the
battery therein. Hatch cover 103 is replaced by following the above
steps in reverse order. This feature is described more fully
below.
FIG. 14 is an exploded perspective view of the hatch cover assembly
showing the component parts thereof. Hatch cover 103 is provided
with means to externally actuate paddle 87. Coupling 106 is adapted
to receive wedge-shaped male end 99 of plunger 84 (FIG. 11).
Torsion spring 107 is received about projection 108 on coupling
106. Moreover, coupling 106 is provided with bore 109 for receiving
straight end 111 of torsion spring 107. Torsion spring 107 has a
90.degree. bend 112 received in a slot (not shown) of hatch cover
103. Hatch cover 103 is provided with hole 113 into which O-ring
110 is inserted for sealingly receiving male connector 114 of knob
104. O-ring 110 is preferably made of neoprene. Male connector 114
is provided with tongues 115 for engagement in grooves 116 of
female projection 108 on coupling 106. When assembled, the
combination of actuator 86 (FIG. 11), plunger 84 (FIG. 11),
coupling 106 and knob 104 form an actuator assembly allowing manual
rotation of knob 104 to be imparted to paddle 87 (FIG. 11). The
torsion spring 107 can be eliminated if the recentering feature
performed by the spring is not desired.
Hatch cover 103 is further provided with a locking mechanism. Latch
105 includes quarter turn male fastener 118. Quarter turn male
fastener 118 is of the half-moon type and is received within the
corresponding quarter turn female fastener 119. A split ring
retainer 123 assists in retention of latch 105. Quarter turn female
fastener 119 has a knurled external surface 121 for tight
engagement within hole 130 in meter cover 98 (FIG. 12). Moreover,
fastener 119 is preferably ultrasonically welded within hole
130.
FIG. 15 is a front elevational view of cover 103 with knob 104 and
latch 105 in the locked (latched) position. Latch 105 is concave,
while knob 104 has a corresponding mating concavity 124. In the
locked position of FIG. 15, the concavity 124 nests with latch 105.
Moreover, concavity 124 and latch 105 are provided with key-shaped
holes 126 and 127, respectively for receiving security tie 128
therethrough. Security tie 128 locks latch 105 and knob 104 in the
position of FIG. 15 to prevent unauthorized access to the meter. In
addition, security ties are commonly provided with tamper
indicators.
In operation, when paddle 87 contacts reset switch 88 the
consumption counter is reset. This is achieved by imparting a
rotation to plunger 84 by rotation of knob 104. The scroll mode is
enabled when paddle 87 is rotated in the opposite direction by
corresponding rotation of plunger 84, imparting rotation to knob
104. In the scroll mode, data may be transmitted between the
emitter/detector and an external reader/programmer through an
optical coupler as described above. When maintaining force is
removed from plunger 84, torsion spring 91 urges paddle 87 away
from the switches, thereby disabling them. Torsion spring biases
paddle 87 to a position approximately half way between the dome
switches. This function of torsion spring 87 prevents accidental
actuation of either switch.
Because of the mating arrangement of knob 104 with coupling 106 and
of coupling 106 with plunger 84, the knob and hatch cover 103 may
be easily removed from hatch 100. Further, the corresponding
tongues 115, grooves 116 and wedge-shapes ensure that the paddle
actuator assembly is correctly reassembled when hatch cover 103 is
repositioned. Hatch cover 103 is installed into hatch opening 101
by first securely rolling top edge 128 of the hatch cover under rim
129 (FIG. 12) of hatch 100. For installation, knob 104 must be
rotated one eighth turn clockwise while latch 105 must be rotated
one quarter turn as shown in FIG. 13. In this position, the quarter
turn fastener elements 118 and 119 (FIG. 14) are in the open
(unfastened) mode. To lock the hatch, latch 105 is rotated
clockwise by one quarter turn, causing the fastener elements to
close (fasten). Then knob 104 is rotated counterclockwise for
approximately one eighth turn to achieve the position of FIG. 15.
The quarter turn fastener parts 105 and 119 are available from
Southco.
While the invention has been illustrated and described in detail in
the drawings and foregoing description, the same is to be
considered as illustrative and not restrictive in character, it
being understood that only the preferred embodiment has been shown
and described and that all changes and modifications that come
within the spirit of the invention are desired to be protected.
* * * * *